COMPARATIVE-ANALYSIS OF METAL AND COMPOSITE-MATERIALS FOR THE PRIMARYSTRUCTURES OF A PATROL CRAFT

This paper compares composite materials to steel and aluminum to be us ed for the primary structures of a patrol craft. The process of select ing materials and fabrication techniques is described with considerati on given to performance, producibility, ease of fabrication, maintaina bility, cost and fire resistance. A design optimization is carried out for each structural panel to select the best compromise between cost and weight. An example of a panel, scantlings and frame spacing optimi zation is described in detail. After carrying out similar optimization s for all parts of the ship structure, a complete structure weight and cost estimate is made and compared for the various materials consider ed. Several composite material options are examined. The respective hu ll girder strength and rigidity of the various structures considered a re compared and the impact of hull girder bending on shaft bearing loa ds is described. The overall impact of using different material types is addressed by using whole-ship design synthesis models to emphasize the importance of structural weight reduction with regard to powering requirements and fuel consumption. Overall ship construction and life cycle costs is also addressed.